The invention concerns a panel comprising at least one pair of complementary locking means at mutually opposite panel edges, wherein the locking means are in the form of positively locking holding profiles with a locking groove and with a complementary locking tongue respectively, wherein at least at the edge of one of the holding profiles the panel surface has an edge break portion, with the proviso that that holding profile which is provided with the edge break portion is provided with an upper contact surfaced beneath the edge break portion and the complementary holding profile is provided with a complementary upper contact surface which is arranged substantially parallel thereto, and wherein a butt joint can be produced by the two contact surfaces in contact with each other, wherein the butt joint is inclined relative to the panel surface and for that purpose one of the contact surfaces is associated with a tongue and is inclined downwardly in the direction of the free end of the tongue in question and the complementary upper contact surface is associated with a groove and is inclined downwardly in the direction of the bottom of the groove in question.
Panels of that kind are used for example to produce floor coverings, in particular being suitable for floatingly laid floor coverings. The panels usually have decorative surfaces.
DE 20 2008 011 589 discloses a panel which has upper contact surfaces, between which a gap can be formed. An edge break portion is proposed, which provides that a gap which occurs is less conspicuous than in the case of a floor covering comprising panels without an edge break portion, which afford a flat floor surface so that gaps show themselves as being clearly visible. The edge break portion of the panels forms for example a V-shaped joint. A gap does not then appear at the surface of the panel, but at the deepest point of such a V-shaped joint, and is then not at all visible for a viewing person in accordance with a respective viewing direction from above. As a result the appearance of a floor covering is less unsightly by virtue of the V-shaped joint or the edge break portion, than in the case of a floor covering comprising panels which does not have an edge break portion and gaps are clearly visible at the surface of a floor covering.
A generic panel is known from US 2010/0018149 A1, namely the embodiment of FIG. 12. Therein a panel is proposed which has complementary locking means is provided on opposing panel edges, wherein one panel edge has an edge break portion and the complementary panel edge also has an edge break portion, which together with the aforementioned edge break portion form a V-groove. The butt joint under the V-groove is inclined relative to the panel surface and has a gap. A small wedge-shaped spring is associated with one of the contact surfaces, which spring is arranged on the upper edge of the panel and is inclined downward in the direction of its free end. A small wedge-shaped groove is associated with the complementary upper contact surface, which groove is located at the upper edge of the complementary panel. This upper contact surface is inclined downwards towards the bottom of the respective groove. The wedge-shaped spring and the wedge-shaped groove contribute, according to this prior art, if at all, only insignificantly to the vertical locking; instead, a tongue and groove is provided elsewhere specifically for the purpose of vertical locking, noted with V1. In this prior art, a locking is to be provided which can produce a relative position of the panels, which is referred to as initially interlocking position. From this position the panels are then movable in the horizontal direction toward or away from each other. In both directions a restoring force should be generated, namely for resetting towards the initially interlocking position. The restoring action is based on an elastic bending of the lower groove wall. Moreover, the lock in the horizontal direction is to be free of play, in which a horizontal position in which the lower groove wall is elastically bent downward is referred to within the meaning of this prior art as free of play.
It is therefore a disadvantage of the above prior art that the panel surface of that panel with the spring provided for the purpose of vertical locking may drop below the level that its panel surface had, as the initially mutually locking position has been taken. The design favors a vertical offset between the locked panel edges, wear of the locking means is amplified and the cohesion of locked panel edges is weakened.